Video service quality assessment method and apparatus

ABSTRACT

A video service quality assessment method and apparatus are provided to resolve a prior-art problem of relatively low accuracy of an assessment result. A monitoring device obtains an identifier of a to-be-monitored channel, an identifier of to-be-monitored user equipment, and configuration information of a video service transmission system; obtains a multicast video stream of the to-be-monitored channel based on the identifier of the to-be-monitored channel; obtains a retransmitted video stream based on the identifier of the to-be-monitored channel, the identifier of the to-be-monitored user equipment, and the configuration information of the video service transmission system; determines a to-be-assessed video stream based on the multicast video stream and the retransmitted video stream; and parses the to-be-assessed video stream, and obtains an assessment result based on a parsing result and the configuration information of the video service transmission system.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2017/087994, filed on Jun. 13, 2017, which claims priority toChinese Patent Application No. 201610430541.7, filed on Jun. 16, 2016.The disclosures of the aforementioned applications are herebyincorporated by reference in their entireties.

TECHNICAL FIELD

The present application relates to the field of communicationstechnologies, and in particular, to a video service quality assessmentmethod and apparatus.

BACKGROUND

Currently, an Internet Protocol television (IPTV) video service isindependently operated and controlled by a telecommunications operator.A user pays the telecommunications operator money, and thetelecommunications operator provides the user with an IPTV videoheadend, a content delivery network (CDN), a set-top box (STB), anothernetwork device ensuring normal running of the IPTV video service, andthe like, and is responsible for paid content of the user and IPTV videoservice quality.

The mean opinion score of video (MOS-V) is an assessment criterion formeasuring IPTV video service quality. This standard is used to detect aprogram source compression impairment and a network transmissionimpairment of a received video, and perform integrated modeling-basedscoring on impact of these impairments on video watching experience of auser based on a specific scoring criterion. The IPTV video servicequality can be determined based on a scoring result.

In the prior art, video service quality is specifically accessed byusing the MOS-V in the following specific implementation solution: Avideo service quality assessment device is deployed in a network. Thedevice captures a multicast video stream, parses a video-relatedparameter, calculates video content complexity and a quantity of bitsper pixel, and assesses an impairment of compression coding on videoquality, namely, a video compression artefacts. Then the device collectsstatistics on a video packet loss status, and assesses a networktransmission error of the packet loss on video quality by usingdifferent models for different error concealment manners. Finally, thedevice comprehensively considers the video compression impairment andthe network transmission impairment to obtain a final MOS-V.

In actual application, a telecommunications operator often uses a seriesof assurance mechanisms, such as an error recovery mechanism and abuffer mechanism used to improve a packet loss error tolerancecapability of an IPTV system, so as to improve IPTV video servicequality. Because in the prior art, these assurance mechanisms are notconsidered in this specific implementation solution for assessing videoservice quality by using the MOS-V, the obtained video compressionimpairment and network transmission impairment cannot reflect a realnetwork status, and consequently an assessment result obtained throughMOS-V-based video quality assessment has relatively low accuracy.

SUMMARY

The present disclosure provides a video service quality assessmentmethod and apparatus, so as to resolve a prior-art problem that anobtained video compression impairment and network transmissionimpairment cannot reflect a real network status, and consequently anassessment result obtained through MOS-V-based video quality assessmenthas relatively low accuracy.

According to a first aspect, the present disclosure provides a videoservice quality assessment method, where the method includes: obtainingan identifier of a to-be-monitored channel, an identifier ofto-be-monitored user equipment, and configuration information of a videoservice transmission system; obtaining a multicast video stream of theto-be-monitored channel based on the identifier of the to-be-monitoredchannel; obtaining, based on the identifier of the to-be-monitoredchannel and the identifier of the to-be-monitored user equipment, avideo stream that is of the to-be-monitored channel and that needs to beretransmitted; obtaining a retransmitted video stream of theto-be-monitored channel based on the identifier of the to-be-monitoredchannel, the identifier of the to-be-monitored user equipment, and theconfiguration information of the video service transmission system;determining a to-be-assessed video stream based on the multicast videostream and at least one of the video stream that needs to beretransmitted and the retransmitted video stream; and parsing theto-be-assessed video stream, and obtaining an assessment result based ona parsing result and the configuration information of the video servicetransmission system.

According to the video service quality assessment method provided in thepresent disclosure, in a process of determining the to-be-assessed videostream, not only the multicast video stream is obtained, but also thevideo stream that needs to be retransmitted and the retransmitted videostream are obtained, and the final video stream used for qualityassessment is determined based on the multicast video stream and the atleast one of the video stream that needs to be retransmitted and theretransmitted video stream. In the prior art, only a multicast videostream is obtained. By comparison, according to the video servicequality assessment method provided in the present disclosure, the atleast one of the video stream that needs to be retransmitted and theretransmitted video stream is further considered, and the to-be-assessedvideo stream can truly reflect a status of receiving a video stream bythe user equipment. Therefore, the assessment result obtained based onthe to-be-assessed video stream is also relatively accurate.

With reference to the first aspect, in a first implementation of thefirst aspect, the obtaining, based on the identifier of theto-be-monitored channel and the identifier of the to-be-monitored userequipment, a video stream that is of the to-be-monitored channel andthat needs to be retransmitted includes: obtaining, based on theidentifier of the to-be-monitored channel and the identifier of theto-be-monitored user equipment, a retransmission request correspondingto the to-be-monitored channel that is sent by the to-be-monitored userequipment, where the retransmission request includes an identifier of apacket that needs to be retransmitted; and obtaining, based on theidentifier of the packet that needs to be retransmitted, the videostream that needs to be retransmitted.

In this implementation, the video stream that needs to be retransmitted,to be specific, a packet that is not successfully received by theto-be-monitored user equipment, may be obtained based on theretransmission request corresponding to the to-be-monitored channel thatis sent by the to-be-monitored user equipment. Therefore, a video streamactually received on a user equipment side in a multicast mode can bedetermined based on the obtained multicast video stream and video streamthat needs to be retransmitted.

With reference to the first aspect, in a second implementation of thefirst aspect, the configuration information of the video servicetransmission system includes an identifier of each device in the videoservice transmission system; the method further includes: determining,based on the configuration information of the video service transmissionsystem, whether the video service transmission system includes aretransmission server; if the video service transmission system includesthe retransmission server, the method further includes: obtaining anidentifier of the retransmission server; and the obtaining aretransmitted video stream of the to-be-monitored channel based on theidentifier of the to-be-monitored channel, the identifier of theto-be-monitored user equipment, and the configuration information of thevideo service transmission system specifically includes: obtaining,based on the identifier of the to-be-monitored channel, the identifierof the to-be-monitored user equipment, and the identifier of theretransmission server, a retransmitted packet sent by the retransmissionserver to the to-be-monitored user equipment; and determining theretransmitted packet as the retransmitted video stream.

In this implementation, it may be determined, by using the configurationinformation of the video service transmission system, whether theretransmission server exists in the system. If the retransmission serverexists, a packet received by the to-be-monitored user equipment throughretransmission, that is, the retransmitted video stream, may bedetermined based on the retransmitted packet sent by the retransmissionserver to the to-be-monitored user equipment; or if the retransmissionserver does not exist, there is no retransmitted video stream. In thisway, the to-be-assessed video stream is determined by considering avideo stream received through retransmission in addition to a videostream received in a multicast mode. The to-be-assessed video streamdetermined in this way can truly reflect a video stream actuallyreceived on a user equipment side, and the assessment result obtainedbased on the video stream is also relatively accurate.

With reference to the second implementation of the first aspect, in athird implementation of the first aspect, the identifier of theto-be-monitored user equipment is an IP address of the to-be-monitoreduser equipment, and the identifier of the retransmission server is an IPaddress of the retransmission server; and if the retransmission serverand another device have a same IP address, the obtaining, based on theidentifier of the to-be-monitored channel, the identifier of theto-be-monitored user equipment, and the identifier of the retransmissionserver, a retransmitted packet sent by the retransmission server to theto-be-monitored user equipment specifically includes: determining, basedon the identifier of the to-be-monitored channel, the IP address of theto-be-monitored user equipment, the IP address of the retransmissionserver, and an encapsulation format of a packet used to transmit a videostream, the retransmitted packet sent by the retransmission server tothe to-be-monitored user equipment.

In this implementation, when the retransmission server and the anotherdevice have the same IP address, for example, when the retransmissionserver and the another device are disposed in an integrated manner, orthe retransmission server and the another device are implemented byusing a same physical device, the retransmitted packet needs to beidentified based on the encapsulation format of the retransmitted packetin addition to a source IP address (the IP address of the retransmissionserver) and a destination IP address (the IP address of theto-be-monitored user equipment) included in the packet, so as todistinguish between packets from the another device and theretransmission server.

With reference to any one of the first aspect, and the first to thethird implementations of the first aspect, in a fourth implementation ofthe first aspect, the configuration information of the video servicetransmission system includes a buffer capacity of the to-be-monitoreduser equipment; and before the obtaining a multicast video stream, avideo stream that needs to be retransmitted, and a retransmitted videostream of the to-be-monitored channel, the method further includes:disposing a buffer based on the buffer capacity of the to-be-monitoreduser equipment, where the buffer is configured to buffer the multicastvideo stream and the retransmitted video stream.

In this implementation, the buffer is disposed based on the buffercapacity of the to-be-monitored user equipment, and is configured tobuffer the obtained multicast video stream and retransmitted videostream, so as to simulate a buffer mechanism of the to-be-monitored userequipment. Therefore, in this implementation, the buffer mechanism ofthe to-be-monitored user equipment is considered in the video servicequality assessment method provided in the present disclosure. Therefore,the status of receiving a video stream on the to-be-monitored userequipment side can be more truly reflected, so that accuracy of theassessment result can be further improved.

According to a second aspect, an embodiment of the present disclosureprovides a video service quality assessment apparatus, where theapparatus includes: an obtaining module, configured to obtain anidentifier of a to-be-monitored channel, an identifier ofto-be-monitored user equipment, and configuration information of a videoservice transmission system; and a processing module, configured to:obtain a multicast video stream of the to-be-monitored channel based onthe identifier of the to-be-monitored channel; obtain, based on theidentifier of the to-be-monitored channel and the identifier of theto-be-monitored user equipment, a video stream that is of theto-be-monitored channel and that needs to be retransmitted; obtain aretransmitted video stream of the to-be-monitored channel based on theidentifier of the to-be-monitored channel, the identifier of theto-be-monitored user equipment, and the configuration information of thevideo service transmission system; determine a to-be-assessed videostream based on the multicast video stream and at least one of the videostream that needs to be retransmitted and the retransmitted videostream; and parse the to-be-assessed video stream, and obtain anassessment result based on a parsing result and the configurationinformation of the video service transmission system.

According to the video service quality assessment apparatus provided inthe present disclosure, when determining the to-be-assessed videostream, the processing module not only obtains the multicast videostream, but also obtains the at least one of the video stream that needsto be retransmitted and the retransmitted video stream, and determines,based on the multicast video stream and the at least one of the videostream that needs to be retransmitted and the retransmitted videostream, the final video stream used for quality assessment. In the priorart, only a multicast video stream is obtained. By comparison, the videoservice quality assessment apparatus provided in the present disclosurefurther considers the at least one of the video stream that needs to beretransmitted and the retransmitted video stream, and the to-be-assessedvideo stream can truly reflect a status of receiving a video stream bythe user equipment. Therefore, the assessment result obtained based onthe to-be-assessed video stream is also relatively accurate.

With reference to the second aspect, in a first implementation of thesecond aspect, the processing module is specifically configured to:obtain, based on the identifier of the to-be-monitored channel and theidentifier of the to-be-monitored user equipment, a retransmissionrequest corresponding to the to-be-monitored channel that is sent by theto-be-monitored user equipment, where the retransmission requestincludes an identifier of a packet that needs to be retransmitted; andobtain, based on the identifier of the packet that needs to beretransmitted, the video stream that needs to be retransmitted.

With reference to the second aspect, in a second implementation of thesecond aspect, the processing module is further configured to: when theconfiguration information of the video service transmission systemincludes an identifier of each device in the video service transmissionsystem, determine, based on the configuration information of the videoservice transmission system, whether the video service transmissionsystem includes a retransmission server; when the video servicetransmission system includes the retransmission server, obtain anidentifier of the retransmission server; obtain, based on the identifierof the to-be-monitored channel, the identifier of the to-be-monitoreduser equipment, and the identifier of the retransmission server, aretransmitted packet sent by the retransmission server to theto-be-monitored user equipment; and determine the retransmitted packetas the retransmitted video stream.

With reference to the second implementation of the second aspect, in athird implementation of the second aspect, the processing module isfurther configured to: when the identifier of the to-be-monitored userequipment is an IP address of the to-be-monitored user equipment, theidentifier of the retransmission server is an IP address of theretransmission server, and the retransmission server and another devicehave a same IP address, determine, based on the identifier of theto-be-monitored channel, the IP address of the to-be-monitored userequipment, the IP address of the retransmission server, and anencapsulation format of a packet used to transmit a video stream, theretransmitted packet sent by the retransmission server to theto-be-monitored user equipment.

With reference to any one of the second aspect, and the first to thethird implementations of the second aspect, in a fourth implementationof the second aspect, the processing module is further configured to:when the configuration information of the video service transmissionsystem includes a buffer capacity of the to-be-monitored user equipment,dispose a buffer based on the buffer capacity of the to-be-monitoreduser equipment, where the buffer is configured to buffer the multicastvideo stream and the retransmitted video stream.

According to a third aspect, an embodiment of the present disclosureprovides a video service quality assessment apparatus, where theapparatus includes a transmitter, a receiver, a memory, a processor, anda bus; the transmitter, the receiver, the memory, and the processor areconnected to each other by using the bus; the transmitter is configuredto send data to another device under the control of the processor; thereceiver is configured to receive, under the control of the processor,data sent by the another device; the memory is configured to storeprogram code; and the processor is configured to execute the programcode, so as to implement the method according to any one of the firstaspect and the implementations of the first aspect.

When determining a to-be-assessed video stream, the video servicequality assessment apparatus provided in the present disclosure not onlyobtains a multicast video stream, but also obtains at least one of avideo stream that needs to be retransmitted and a retransmitted videostream, and determines, based on the multicast video stream and the atleast one of the video stream that needs to be retransmitted and theretransmitted video stream, the final video stream used for qualityassessment. In the prior art, only a multicast video stream is obtained.By comparison, the video service quality assessment apparatus providedin the present disclosure further considers the at least one of thevideo stream that needs to be retransmitted and the retransmitted videostream, and the to-be-assessed video stream can truly reflect a statusof receiving a video stream by user equipment. Therefore, an assessmentresult obtained based on the to-be-assessed video stream is alsorelatively accurate.

BRIEF DESCRIPTION OF DRAWINGS

To describe the technical solutions in the embodiments of the presentdisclosure or in the prior art more clearly, the following brieflydescribes the accompanying drawings required for describing theembodiments.

FIG. 1 is a schematic architectural diagram of a video servicetransmission system according to an embodiment of the presentdisclosure;

FIG. 2 is a schematic diagram of a specific implementation process ofretransmitting a packet by using a retransmission server according to anembodiment of the present disclosure;

FIG. 3 is a schematic flowchart of a video service quality assessmentmethod according to an embodiment of the present disclosure;

FIG. 4A and FIG. 4B are a schematic flowchart of another video servicequality assessment method according to an embodiment of the presentdisclosure;

FIG. 5 is a schematic structural diagram of a video service qualityassessment apparatus according to an embodiment of the presentdisclosure; and

FIG. 6 is a schematic structural diagram of another video servicequality assessment apparatus according to an embodiment of the presentdisclosure.

DESCRIPTION OF EMBODIMENTS

The following describes the technical solutions in the embodiments withreference to the accompanying drawings in the embodiments.

As shown in FIG. 1, an embodiment of the present disclosure provides avideo service transmission system. The system includes a managementdevice 101, a headend 102, a monitoring device 103, and user equipment104. The management device 101 is configured to manage, configure, andmonitor a running status of each device in the video servicetransmission system and a video stream transmission status. In thisembodiment of the present disclosure, the management device is furtherconfigured to send a monitoring instruction to the monitoring device.The headend 102 is configured to: encode a to-be-transmitted videoservice, push a video stream, and the like. The monitoring device 103 isconfigured to monitor, according to the monitoring instruction of themanagement device 101, quality of a video stream transmitted in anetwork, and may be specifically a monitoring device shown in FIG. 6.The user equipment 104 is a device on a user side that is configured todecode and play a video, for example, an STB.

Optionally, the video service transmission system further includesanother network device ensuring IPTV video service quality. For example,a fast channel change (FCC) technology is usually used for a problem ofa slow channel change in a current play process of an IPTV videoservice. In this case, the system further includes an FCC server. Foranother example, phenomena such as pixelation and erratic display causedby a packet loss are prone to occur in an IPTV video servicetransmission process. To resolve the packet loss problem, aretransmission (RET) mechanism is usually further used in the videoservice transmission system. In this case, the system further includes aRET server. The FCC server and the RET server may be deployed on a samephysical device, or may be deployed on different physical devices.

It should be noted that FIG. 1 further shows a RET server 105, but showsno FCC server.

In actual application, a video service in the video service transmissionsystem may be carried by using a Real-Time Transport Protocol (RTP)packet. The video stream mentioned in this embodiment of the presentdisclosure may be an RTP video stream. Each RTP packet is correspondingto one sequence number. Each RTP packet in the RTP video stream may belocated based on a value of the sequence number because a sequencenumber of an RTP packet is one larger than that of a previous RTP packetbased on an RTP packet encapsulation sequence. Therefore, the sequencenumber may be used to detect a packet loss status. When detecting apacket loss or an error packet, the user equipment may send aretransmission request to the retransmission server to request toreceive a packet again that is not successfully received in a multicastmode.

As shown in FIG. 2, when the video service transmission system includesthe retransmission server, a specific implementation process ofretransmitting a packet by using the retransmission server includes thefollowing steps.

201. The headend sends a multicast video service stream to theretransmission server.

202. The retransmission server receives and buffers the multicast videoservice stream sent by the headend, and forwards the multicast videoservice stream to the user equipment.

203. The user equipment and the retransmission server establish asession (RET session) used to retransmit a packet with each other.

204. The user equipment detects whether there is a packet loss or anerror packet.

If a packet loss or an error packet is found, step 205 and subsequentsteps are performed.

205. The user equipment sends a retransmission request to theretransmission server in a unicast mode.

Internet Engineering Task Force (IETF) RFC 4585 defines a specificimplementation form of the retransmission request. The retransmissionrequest may be an RTP Control Protocol (RTCP) NACK request. In addition,according to RFC 4585, one RTCP NACK request packet may be used torequest to retransmit a plurality of RTP packets.

206. The retransmission server searches, based on a channel identifierand a packet identifier (PID) in the received retransmission request,for an RTP packet buffered in a video stream buffer area of acorresponding channel.

In addition, IETF RFC 4588 further defines an RTP encapsulation formatof a retransmitted packet.

207. The retransmission server sends the RTP packet corresponding to thePID in the retransmission request to the user equipment if theretransmission server finds the RTP packet.

208. After receiving the retransmitted RTP packet, the user equipmentdecodes all RTP packets and plays a video.

As shown in FIG. 3, an embodiment of the present disclosure provides avideo service quality assessment method. The method may be applied tothe video service transmission system shown in FIG. 1 and theapplication scenario shown in FIG. 2. The method may be performed by amonitoring device in the video service transmission system. The methodincludes the following steps.

301. Obtain an identifier of a to-be-monitored channel, an identifier ofto-be-monitored user equipment, and configuration information of thevideo service transmission system.

The identifier of the to-be-monitored channel may be a channel number ofthe to-be-monitored channel, a synchronous source (SSRC) identifier (ID)corresponding to the to-be-monitored channel, or the like. Theidentifier of the to-be-monitored user equipment may be an IP address orthe like of the to-be-monitored user equipment.

The configuration information of the video service transmission systemincludes an identifier of each device included in the video servicetransmission system, such as an IP address. Optionally, theconfiguration information of the video service transmission systemfurther includes a video coding configuration parameter of a headend,such as a coding type, a frame rate, and a resolution, a buffer capacityof the to-be-monitored user equipment, and a decoding parameter of theto-be-monitored user equipment, such as an error concealment manner. Theconfiguration information may further include other attributeinformation of the video service transmission system, for example, anerror tolerance capability deployed in the transmission system.

Optionally, in a specific implementation process of this step, theidentifier of the to-be-monitored channel and the identifier of theto-be-monitored user equipment may be obtained by the monitoring deviceby using a management device. The configuration information of the videoservice transmission system may be obtained by the monitoring device byusing the management device, or may be obtained by the monitoring deviceby capturing a video stream or a RET session. For example, when thevideo stream is not scrambled, the monitoring device may capture andparse the video stream to obtain information such as a coding type, orthe monitoring device may capture and parse the RET session to obtain anidentifier of a RET server and the like.

302. Obtain a multicast video stream of the to-be-monitored channelbased on the identifier of the to-be-monitored channel; obtain, based onthe identifier of the to-be-monitored channel and the identifier of theto-be-monitored user equipment, a video stream that is of theto-be-monitored channel and that needs to be retransmitted; and obtain aretransmitted video stream of the to-be-monitored channel based on theidentifier of the to-be-monitored channel, the identifier of theto-be-monitored user equipment, and the configuration information of thevideo service transmission system.

The multicast video stream is a video stream sent by the headend to amulticast group including a plurality of user equipments. The monitoringdevice may obtain, based on the channel number, the multicast videostream corresponding to the to-be-monitored channel.

The video stream that needs to be retransmitted is a multicast videostream that is not successfully received by the user equipment. Forexample, if the user equipment has not received any packets because apacket loss occurs in a multicast video stream transmission process,these packets form the video stream that needs to be retransmitted.

The retransmitted video stream is a video stream sent, for the purposeof resolving the packet loss problem, by the retransmission server tothe user equipment based on a retransmission request of the userequipment after the multicast video stream is sent. The video stream isa video stream that is not successfully received by the user equipmentin a multicast mode.

Optionally, the video stream in this embodiment of the presentdisclosure includes an RTP packet.

303. Determine a to-be-assessed video stream based on the multicastvideo stream and at least one of the video stream that needs to beretransmitted and the retransmitted video stream.

In a specific implementation process of this step, the to-be-assessedvideo stream may be determined in the following three manners.

Manner 1: The to-be-assessed video stream is determined by using themulticast video stream and the video stream that needs to beretransmitted.

This implementation is mainly applied to an application scenario inwhich the video service transmission system does not include theretransmission server. There is no retransmitted video stream becausethe video service transmission system does not include theretransmission server. In this implementation, because locations of themonitoring device and the user equipment in the video servicetransmission system are different, a packet loss may occur when themonitoring device transmits the multicast video stream to the userequipment. Therefore, the multicast video stream captured by themonitoring device cannot truly reflect a multicast video stream receivedon a user equipment side. Therefore, the monitoring device further needsto determine, based on a packet that is not successfully received by theuser equipment in the multicast mode, the multicast video streamactually received on the user equipment side. For example, the multicastvideo stream captured by the monitoring device includes packets 1 to 10,and the video stream of the user equipment that needs to beretransmitted includes packets 2 and 3 based on the retransmissionrequest sent by the user equipment, that is, the user equipment actuallyhas not received the packets 2 and 3. In this case, the multicast videostream actually received by the user equipment includes packets 1, and 4to 10. Therefore, the video stream actually received on the userequipment side in the multicast mode is obtained through estimation byusing the multicast video stream and the video stream that needs to beretransmitted, and the video stream is determined as the to-be-assessedvideo stream.

Manner 2: The to-be-assessed video stream is determined by using themulticast video stream and the retransmitted video stream.

This implementation is mainly applied to an application scenario inwhich the video service transmission system includes the retransmissionserver. The retransmission server usually sends, to the user equipmentafter receiving the retransmission request sent by the user equipment,all data that needs to be retransmitted. In this case, the retransmittedvideo stream is the same as the video stream that needs to beretransmitted. Therefore, the to-be-assessed video stream determined byusing the multicast video stream and the retransmitted video stream canrelatively accurately reflect a video stream actually received on a userequipment side.

Manner 3: The to-be-assessed video stream is determined by using themulticast video stream, the video stream that needs to be retransmitted,and the retransmitted video stream.

This implementation is mainly applied to an application scenario inwhich the video service transmission system includes the retransmissionserver. In the application scenario, the retransmitted video stream sentby the retransmission server may not be totally the same as the videostream that needs to be retransmitted, for example, when a packet lossoccurs again in a retransmission process. In this implementation, aservice stream determined by using the multicast video stream and thevideo stream that needs to be retransmitted is a video stream actuallyreceived by the user equipment in the multicast mode, and theretransmitted video stream is a video stream actually received by theuser equipment through retransmission. Therefore, the to-be-assessedvideo stream determined in this implementation can more accuratelyreflect a video stream actually received by the user equipment than thatin the Manner 2.

304. Parse the to-be-assessed video stream, and obtain an assessmentresult based on a parsing result and the configuration information ofthe video service transmission system.

The configuration information of the video service transmission systemincludes the video coding configuration parameter used by the headend toencode a video, such as the coding type, the frame rate, and theresolution, and the decoding parameter of the to-be-monitored userequipment, such as the error concealment manner.

In a specific implementation process of this step, the monitoring devicesimulates a decoding behavior of the to-be-monitored user equipmentbased on the decoding parameter, sorts an out-of-order video stream,extracts video frames at a constant speed based on the frame rate or aspecific time interval, and obtains attribute information of the videostream, such as a frame type, a frame size, a frame packet loss event,and a lost packet count; then determines a bit rate based on the videocoding configuration parameter and the frame size, and determines avideo compression impairment; further needs to determine a networktransmission impairment based on the decoding parameter, the frame type,the frame size, the frame packet loss event, the lost packet count, andthe like; and finally, comprehensively considers the video compressionimpairment and the network transmission impairment to obtain a finalMOS-V.

For a specific implementation process of this step, refer to the priorart, and details are not described herein.

According to the video service quality assessment method provided inthis embodiment of the present disclosure, when determining theto-be-assessed video stream, the monitoring device not only obtains themulticast video stream, but also obtains the video stream that needs tobe retransmitted and the retransmitted video stream, and determines,based on the multicast video stream and the at least one of the videostream that needs to be retransmitted and the retransmitted videostream, the final video stream used for quality assessment. In the priorart, only a multicast video stream is obtained. By comparison, accordingto the video service quality assessment method provided in thisembodiment of the present disclosure, the at least one of the videostream that needs to be retransmitted and the retransmitted video streamis further considered, and the to-be-assessed video stream can trulyreflect a status of receiving a video stream by the user equipment.Therefore, the assessment result obtained based on the to-be-assessedvideo stream is also relatively accurate.

Optionally, in an implementation of step 302, the obtaining, based onthe identifier of the to-be-monitored channel and the identifier of theto-be-monitored user equipment, a video stream that is of theto-be-monitored channel and that needs to be retransmitted includes:

obtaining, based on the identifier of the to-be-monitored channel andthe identifier of the to-be-monitored user equipment, a retransmissionrequest corresponding to the to-be-monitored channel that is sent by theto-be-monitored user equipment, where the retransmission requestincludes an identifier of a packet that needs to be retransmitted; andobtaining, based on the identifier of the packet that needs to beretransmitted, the video stream that needs to be retransmitted.

In actual application, the user equipment performs error and packet lossdetection on a received multicast video stream. If the user equipmentfinds a packet loss or an error packet, the user equipment initiates theretransmission request to the RET server. The retransmission request mayinclude identifiers of a plurality of packets that need to beretransmitted.

In this implementation, the video stream that needs to be retransmitted,to be specific, a packet that is not successfully received by theto-be-monitored user equipment, may be obtained based on theretransmission request sent by the to-be-monitored user equipment.Therefore, the video stream actually received on the user equipment sidein the multicast mode can be determined based on the obtained multicastvideo stream and video stream that needs to be retransmitted.

Optionally, the configuration information of the video servicetransmission system includes an identifier of each device in the videoservice transmission system, such as an IP address of the headend and anIP address of the retransmission server. The method further includes:determining, based on the configuration information of the video servicetransmission system, whether the video service transmission systemincludes a retransmission server; and if the video service transmissionsystem includes the retransmission server, correspondingly, in animplementation of step 302, the obtaining a retransmitted video streambased on the identifier of the to-be-monitored channel, the identifierof the to-be-monitored user equipment, and the configuration informationof the video service transmission system specifically includes:

obtaining an identifier of the retransmission server; obtaining, basedon the identifier of the to-be-monitored channel, the identifier of theto-be-monitored user equipment, and the identifier of the retransmissionserver, a retransmitted packet sent by the retransmission server to theto-be-monitored user equipment; and determining the retransmitted packetas the retransmitted video stream.

Optionally, the identifier of the to-be-monitored user equipment is anIP address of the to-be-monitored user equipment, and the identifier ofthe retransmission server is an IP address of the retransmission server.In this implementation, if the retransmission server and another devicehave a same IP address, in a process of determining the retransmittedpacket, the retransmitted packet sent by the retransmission server tothe to-be-monitored user equipment needs to be determined based on anencapsulation format of a packet used to transmit a video stream inaddition to the identifier of the to-be-monitored channel, the IPaddress of the to-be-monitored user equipment, and the IP address of theretransmission server.

In this implementation, it may be determined, by using the configurationinformation of the video service transmission system, whether theretransmission server exists in the system. If the retransmission serverexists, a packet received by the to-be-monitored user equipment throughretransmission, that is, the retransmitted video stream, may bedetermined based on the retransmitted packet sent by the retransmissionserver to the to-be-monitored user equipment; or if the retransmissionserver does not exist, there is no retransmitted video stream. In thisway, the to-be-assessed video stream is determined by considering thevideo stream received through retransmission in addition to themulticast video stream received in the multicast mode. Theto-be-assessed video stream determined in this way can truly reflect avideo stream actually received by the user equipment, and the assessmentresult obtained based on the video stream is also relatively accurate.

Optionally, the configuration information of the video servicetransmission system includes a buffer capacity of the to-be-monitoreduser equipment. Correspondingly, before the obtaining a multicast videostream, a video stream that needs to be retransmitted, and aretransmitted video stream, the method further includes: disposing abuffer based on the buffer capacity of the to-be-monitored userequipment, where the buffer is configured to buffer the multicast videostream and the retransmitted video stream.

In this implementation, the buffer is disposed based on the buffercapacity of the to-be-monitored user equipment, and is configured tobuffer the obtained multicast video stream and retransmitted videostream, so as to simulate a buffer mechanism of the to-be-monitored userequipment. Therefore, in this implementation, the buffer mechanism ofthe to-be-monitored user equipment is considered in the video servicequality assessment method provided in the present disclosure. Therefore,the status of receiving a video stream on the to-be-monitored userequipment side can be more truly reflected, so that accuracy of theassessment result can be further improved.

As shown in FIG. 4A and FIG. 4B, for example, the video stream is an RTPvideo stream and the to-be-monitored user equipment is an STB. Anembodiment of the present disclosure further provides a video servicequality assessment method. The method may be applied to the videoservice transmission system shown in FIG. 1 and the application scenarioshown in FIG. 2. The method includes the following steps.

401. A headend sends a multicast RTP video stream to a retransmissionserver.

402. The retransmission server receives and buffers the multicast RTPvideo stream sent by the headend, and forwards the multicast RTP videostream to an STB.

403. A management device sends a monitoring instruction to a monitoringdevice, where the monitoring instruction includes an identifier of ato-be-monitored channel and an identifier of the STB.

404. The management device obtains configuration information of thevideo service transmission system, and sends the configurationinformation to the monitoring device.

The configuration information includes an identifier of each device,such as an IP address, a video coding configuration parameter of theheadend, such as a coding type, a frame rate, and a resolution, a buffercapacity of the STB, and a decoding parameter of the STB, such as anerror concealment manner.

An IPTV video service is independently operated and totally controlledby a telecommunications operator, and an IPTV video headend, a STB, andthe like are provided by the telecommunications operator for a user.Therefore, the management device may pre-obtain the configurationinformation of the video service transmission system and send theconfiguration information to the monitoring device.

405. The monitoring device disposes a buffer based on a buffer capacityof the STB, and buffers the multicast RTP video stream in the buffer.

406. The STB and the retransmission server establish a RET session witheach other.

407. The STB detects whether there is a packet loss or an error packetby detecting a sequence number of an RTP packet.

If a packet loss or an error packet is found, step 408 and subsequentsteps are performed.

408. The STB sends a retransmission request to the retransmissionserver.

The retransmission request includes an identifier of an RTP packet thatneeds to be retransmitted.

409. The monitoring device captures the retransmission request, andobtains, based on an identifier that is carried in the request and thatis of an RTP packet that needs to be retransmitted, a video stream thatneeds to be retransmitted.

410. The retransmission server searches a video stream buffer area ofthe corresponding channel based on a channel identifier and a packetidentifier in the received retransmission request.

411. If the retransmission server finds an RTP packet corresponding tothe packet identifier, the retransmission server encapsulates the foundRTP packet and then sends the encapsulated RTP packet to the STB.

412. The monitoring device captures and buffers a unicast RTPretransmission packet sent by the retransmission server to the STB.

413. The monitoring device obtains a to-be-monitored RTP video streambased on the buffered multicast RTP video stream and at least one of thevideo stream that needs to be retransmitted and the retransmittedunicast RTP video stream.

414. The monitoring device parses the to-be-monitored RTP video stream,and obtains an assessment result of the to-be-monitored RTP video streambased on a parsing result and the configuration information.

According to the video service quality assessment method provided inthis embodiment of the present disclosure, when determining ato-be-assessed video stream, the monitoring device not only obtains themulticast video stream, but also obtains the video stream that needs tobe retransmitted and the retransmitted video stream, and determines,based on the multicast video stream and the at least one of the videostream that needs to be retransmitted and the retransmitted videostream, the final video stream used for quality assessment. In the priorart, only a multicast video stream is obtained. By comparison, accordingto the video service quality assessment method provided in thisembodiment of the present disclosure, the at least one of the videostream that needs to be retransmitted and the retransmitted video streamis further considered, and the to-be-assessed video stream can trulyreflect a status of receiving a video stream by the user equipment.Therefore, the assessment result obtained based on the to-be-assessedvideo stream is also relatively accurate.

As shown in FIG. 5, an embodiment of the present disclosure provides avideo service quality assessment apparatus, configured to perform themethod in either of the embodiments in FIG. 3 and FIG. 4A and FIG. 4B.The apparatus includes an obtaining module 501 and a processing module502.

The obtaining module 501 is configured to obtain an identifier of ato-be-monitored channel, an identifier of to-be-monitored userequipment, and configuration information of a video service transmissionsystem.

The obtaining module 501 may be a physical device or a virtual modulethat can implement the foregoing function. In specific application, fora specific processing process of the obtaining module 501, refer to step301 described above, and details are not described herein again.

The processing module 502 is configured to: obtain a multicast videostream of the to-be-monitored channel based on the identifier of theto-be-monitored channel; obtain, based on the identifier of theto-be-monitored channel and the identifier of the to-be-monitored userequipment, a video stream that is of the to-be-monitored channel andthat needs to be retransmitted; obtain a retransmitted video stream ofthe to-be-monitored channel based on the identifier of theto-be-monitored channel, the identifier of the to-be-monitored userequipment, and the configuration information of the video servicetransmission system; determine a to-be-assessed video stream based onthe multicast video stream and at least one of the video stream thatneeds to be retransmitted and the retransmitted video stream; and parsethe to-be-assessed video stream, and obtain an assessment result basedon a parsing result and the configuration information of the videoservice transmission system.

The processing module 502 may be a physical device or a virtual modulethat can implement the foregoing function. In specific application, fora specific processing process of the processing module 502, refer tostep 302 to step 304 described above, and details are not describedherein again.

According to the video service quality assessment apparatus provided inthis embodiment of the present disclosure, when determining theto-be-assessed video stream, the processing module not only obtains themulticast video stream, but also obtains the at least one of the videostream that needs to be retransmitted and the retransmitted videostream, and determines, based on the multicast video stream and the atleast one of the video stream that needs to be retransmitted and theretransmitted video stream, the final video stream used for qualityassessment. In the prior art, only a multicast video stream is obtained.By comparison, the video service quality assessment apparatus providedin the present disclosure further considers the at least one of thevideo stream that needs to be retransmitted and the retransmitted videostream, and the to-be-assessed video stream can truly reflect a statusof receiving a video stream by the user equipment. Therefore, theassessment result obtained based on the to-be-assessed video stream isalso relatively accurate.

Optionally, the processing module 502 is specifically configured to:obtain, based on the identifier of the to-be-monitored channel and theidentifier of the to-be-monitored user equipment, a retransmissionrequest corresponding to the to-be-monitored channel that is sent by theto-be-monitored user equipment, where the retransmission requestincludes an identifier of a packet that needs to be retransmitted; andobtain, based on the identifier of the packet that needs to beretransmitted, the video stream that needs to be retransmitted.

Optionally, the processing module 502 is further configured to: when theconfiguration information of the video service transmission systemincludes an identifier of each device in the video service transmissionsystem, determine, based on the configuration information of the videoservice transmission system, whether the video service transmissionsystem includes a retransmission server; when the video servicetransmission system includes the retransmission server, obtain anidentifier of the retransmission server; obtain, based on the identifierof the to-be-monitored channel, the identifier of the to-be-monitoreduser equipment, and the identifier of the retransmission server, aretransmitted packet sent by the retransmission server to theto-be-monitored user equipment; and determine the retransmitted packetas the retransmitted video stream.

Optionally, the processing module 502 is further configured to: when theidentifier of the to-be-monitored user equipment is an IP address of theto-be-monitored user equipment, the identifier of the retransmissionserver is an IP address of the retransmission server, and theretransmission server and another device have a same IP address,determine, based on the identifier of the to-be-monitored channel, theIP address of the to-be-monitored user equipment, the IP address of theretransmission server, and an encapsulation format of a packet used totransmit a video stream, the retransmitted packet sent by theretransmission server to the to-be-monitored user equipment.

Optionally, the processing module 502 is further configured to: when theconfiguration information of the video service transmission systemincludes a buffer capacity of the to-be-monitored user equipment,dispose a buffer based on the buffer capacity of the to-be-monitoreduser equipment, where the buffer is configured to buffer the multicastvideo stream and the retransmitted video stream.

It should be noted that, in the embodiments provided in thisapplication, it should be understood that the disclosed system,apparatus, and method may be implemented in other manners. For example,the apparatus embodiment described above is merely an example. Forexample, division of the modules is merely logical function division andmay be other division in actual implementation. For example, a pluralityof modules or components may be combined or integrated into anothersystem, or some features may be ignored or not performed. In addition,the displayed or discussed mutual couplings or direct couplings orcommunication connections may be implemented by using some interfaces.The indirect couplings or communication connections between theapparatuses or modules may be implemented in electronic, mechanical, orother forms.

The modules described as separate parts may or may not be physicallyseparate, and parts displayed as modules may or may not be physicalmodules, that is, may be located in one position, or may be distributedon a plurality of network modules. Some or all of the modules may beselected according to actual needs to achieve the objectives of thesolutions of the embodiments.

In addition, function modules in the embodiments of the presentdisclosure may exist alone physically, or two or more modules may beintegrated into one module. The integrated module may be implemented ina form of hardware, or may be implemented in a form of a softwarefunction module.

When the integrated module is implemented in the form of a softwarefunction module and sold or used as an independent product, theintegrated module may be stored in a computer-readable storage medium.Based on such an understanding, the technical solutions of the presentdisclosure essentially, or the part contributing to the prior art, orall or some of the technical solutions may be implemented in the form ofa software product. The computer software product is stored in a storagemedium and includes several instructions for instructing a computerdevice (which may be a personal computer, a server, a network device, orthe like) or a processor to perform all or some of the steps of themethods described in the embodiments of the present disclosure. Thestorage medium includes: any medium that can store program code, such asa USB flash drive, a removable hard disk, a read-only memory, a randomaccess memory (RAM), a magnetic disk, or an optical disc.

As shown in FIG. 6, an embodiment of the present disclosure provides avideo service quality assessment apparatus. The apparatus may be amonitoring device, and is configured to perform the method in either ofthe embodiments in FIG. 3 and FIG. 4A and FIG. 4B. The apparatusincludes a transmitter 601, a receiver 602, a memory 603, a processor604, and a bus 605. The transmitter 601, the receiver 602, the memory603, and the processor 604 are connected to each other by using the bus605.

The transmitter 601 is configured to send data to another device underthe control of the processor 604.

The receiver 602 is configured to receive, under the control of theprocessor 604, data sent by the another device.

The memory 603 is configured to store program code.

The processor 604 is configured to execute the program code, so as toimplement the method shown in FIG. 3 or FIG. 4A and FIG. 4B.

When determining a to-be-assessed video stream, the video servicequality assessment apparatus provided in the present disclosure not onlyobtains a multicast video stream, but also obtains at least one of avideo stream that needs to be retransmitted and a retransmitted videostream, and determines, based on the multicast video stream and the atleast one of the video stream that needs to be retransmitted and theretransmitted video stream, the final video stream used for qualityassessment. In the prior art, only a multicast video stream is obtained.By comparison, the video service quality assessment apparatus providedin the present disclosure further considers the at least one of thevideo stream that needs to be retransmitted and the retransmitted videostream, and the to-be-assessed video stream can truly reflect a statusof receiving a video stream by user equipment. Therefore, an assessmentresult obtained based on the to-be-assessed video stream is alsorelatively accurate.

It should be noted that the memory 603 described in this embodiment ofthe present disclosure may be a storage apparatus, or may be acollective term for a plurality of storage elements, and is configuredto store executable program code and the like. In addition, the memorymay include a RAM or a ROM, or may include a non-volatile memory, suchas a magnetic disk memory or a flash.

The processor 604 may be a processor, or may be a collective term for aplurality of processing elements. For example, the processor may be acentral processing unit (CPU), or may be an application-specificintegrated circuit (ASIC), or may be one or more integrated circuitsconfigured to implement the embodiments of the present disclosure, forexample, one or more digital signal processors (DSP) or one or morefield-programmable gate arrays (FPGA).

The bus 605 may be an industry standard architecture (ISA) bus, aperipheral component interconnect (PCI) bus, an extended industrystandard architecture (EISA) bus, or the like. The bus 605 may fall intoan address bus, a data bus, a control bus, and the like. For ease ofrepresentation, only one thick line is used to represent the bus in FIG.6, but this does not mean that there is only one bus or only one type ofbus.

The foregoing descriptions are merely specific implementations of thepresent disclosure, but are not intended to limit the protection scopeof the present disclosure. Any variation or replacement readily figuredout by a person skilled in the art within the technical scope disclosedin the present disclosure shall fall within the protection scope of thepresent disclosure.

What is claimed is:
 1. A video service quality assessment apparatuscomprising: a processor; and a non-transitory computer readable mediumwhich comprising computer-executable instructions which, when executedby the processor, cause the apparatus to: obtain an identifier of ato-be-monitored channel, an identifier of to-be-monitored userequipment, and configuration information of a video service transmissionsystem, obtain a multicast video stream of the to-be-monitored channelbased on the identifier of the to-be-monitored channel, obtain aretransmitted video stream of the to-be-monitored channel based on theidentifier of the to-be-monitored channel, the identifier of theto-be-monitored user equipment, and the configuration information of thevideo service transmission system, determine a to-be-assessed videostream based on the multicast video stream and the retransmitted videostream, and parse the to-be-assessed video stream, and obtain anassessment result based on a parsing result and the configurationinformation of the video service transmission system.
 2. The apparatusaccording to claim 1, wherein the computer-executable instructions, whenexecuted by the processor, cause the apparatus to: obtain, based on theidentifier of the to-be-monitored channel and the identifier of theto-be-monitored user equipment, a video stream that is of theto-be-monitored channel and that needs to be retransmitted; anddetermine the to-be-assessed video stream based on the multicast videostream, the retransmitted video stream and the video stream that needsto be retransmitted.
 3. The apparatus according to claim 2, wherein toobtain, based on the identifier of the to-be-monitored channel and theidentifier of the to-be-monitored user equipment, a video stream that isof the to-be-monitored channel and that needs to be retransmitted, thecomputer-executable instructions, when executed by the processor,further cause the apparatus to: obtain, based on the identifier of theto-be-monitored channel and the identifier of the to-be-monitored userequipment, a retransmission request corresponding to the to-be-monitoredchannel that is sent by the to-be-monitored user equipment, wherein theretransmission request comprises an identifier of a packet that needs tobe retransmitted; and obtain, based on the identifier of the packet thatneeds to be retransmitted, the video stream that needs to beretransmitted.
 4. The apparatus according to claim 1, wherein: theconfiguration information of the video service transmission systemcomprises an identifier of each device in the video service transmissionsystem; the computer-executable instructions, when executed by theprocessor, cause the apparatus to: determine, based on the configurationinformation of the video service transmission system, whether the videoservice transmission system comprises a retransmission server, and whenthe video service transmission system comprises the retransmissionserver, obtain an identifier of the retransmission server; and to obtaina retransmitted video stream of the to-be-monitored channel based on theidentifier of the to-be-monitored channel, the identifier of theto-be-monitored user equipment, and the configuration information of thevideo service transmission system, the computer-executable instructions,when executed by the processor, further cause the apparatus to: obtain,based on the identifier of the to-be-monitored channel, the identifierof the to-be-monitored user equipment, and the identifier of theretransmission server, a retransmitted packet sent by the retransmissionserver to the to-be-monitored user equipment, and determine theretransmitted packet as the retransmitted video stream.
 5. The apparatusaccording to claim 4, wherein: the identifier of the to-be-monitoreduser equipment is an IP address of the to-be-monitored user equipment,and the identifier of the retransmission server is an IP address of theretransmission server; and when the retransmission server and anotherdevice have a same IP address, to obtain, based on the identifier of theto-be-monitored channel, the identifier of the to-be-monitored userequipment, and the identifier of the retransmission server, aretransmitted packet sent by the retransmission server to theto-be-monitored user equipment, the computer-executable instructions,when executed by the processor, further cause the apparatus to:determine, based on the identifier of the to-be-monitored channel, theIP address of the to-be-monitored user equipment, the IP address of theretransmission server, and an encapsulation format of a packet used totransmit a video stream, the retransmitted packet sent by theretransmission server to the to-be-monitored user equipment.
 6. Theapparatus according to claim 1, wherein: the configuration informationof the video service transmission system comprises a buffer capacity ofthe to-be-monitored user equipment; and before obtaining a multicastvideo stream, and a retransmitted video stream of the to-be-monitoredchannel, the computer-executable instructions computer-executableinstructions, when executed by the processor, cause the apparatus to:dispose of a buffer based on the buffer capacity of the to-be-monitoreduser equipment, wherein the buffer is configured to buffer the multicastvideo stream and the retransmitted video stream.
 7. A video servicequality assessment apparatus comprising: a processor; and anon-transitory computer readable medium comprising computer-executableinstructions which, when executed by the processor, cause the apparatusto: obtain an identifier of a to-be-monitored channel, an identifier ofto-be-monitored user equipment, and configuration information of a videoservice transmission system, obtain a multicast video stream of theto-be-monitored channel based on the identifier of the to-be-monitoredchannel, obtain, based on the identifier of the to-be-monitored channeland the identifier of the to-be-monitored user equipment, a video streamthat is of the to-be-monitored channel and that needs to beretransmitted, determine a to-be-assessed video stream based on themulticast video stream and the video stream that needs to beretransmitted, and parse the to-be-assessed video stream, and obtain anassessment result based on a parsing result and the configurationinformation of the video service transmission system.
 8. The apparatusaccording to claim 7, wherein to obtain, based on the identifier of theto-be-monitored channel and the identifier of the to-be-monitored userequipment, a video stream that is of the to-be-monitored channel andthat needs to be retransmitted, the computer-executable instructions,when executed by the processor, cause the apparatus to: obtain, based onthe identifier of the to-be-monitored channel and the identifier of theto-be-monitored user equipment, a retransmission request correspondingto the to-be-monitored channel that is sent by the to-be-monitored userequipment, wherein the retransmission request comprises an identifier ofa packet that needs to be retransmitted; and obtain, based on theidentifier of the packet that needs to be retransmitted, the videostream that needs to be retransmitted.
 9. A video service qualityassessment method, comprising: obtaining an identifier of ato-be-monitored channel, an identifier of to-be-monitored userequipment, and configuration information of a video service transmissionsystem; obtaining a multicast video stream of the to-be-monitoredchannel based on the identifier of the to-be-monitored channel;obtaining at least one of: a video stream that is of the to-be-monitoredchannel and that needs to be retransmitted, or a retransmitted videostream of the to-be-monitored channel, based on the identifier of theto-be-monitored channel and the identifier of the to-be-monitored userequipment; determining a to-be-assessed video stream based on themulticast video stream and at least one of: the video stream that needsto be retransmitted or the retransmitted video stream; and parsing theto-be-assessed video stream, and obtaining an assessment result based ona parsing result and the configuration information of the video servicetransmission system.
 10. The method according to claim 9, whereinobtaining the video stream that needs to be retransmitted comprises:obtaining, based on the identifier of the to-be-monitored channel andthe identifier of the to-be-monitored user equipment, a retransmissionrequest corresponding to the to-be-monitored channel that is sent by theto-be-monitored user equipment, wherein the retransmission requestcomprises an identifier of a packet that needs to be retransmitted; andobtaining, based on the identifier of the packet that needs to beretransmitted, the video stream that needs to be retransmitted.
 11. Themethod according to claim 9, wherein the retransmitted video stream ofthe to-be-monitored channel is obtained based on the identifier of theto-be-monitored channel, the identifier of the to-be-monitored userequipment, and the configuration information of the video servicetransmission system.
 12. The method according to claim 11, wherein: theconfiguration information of the video service transmission systemcomprises an identifier of each device in the video service transmissionsystem; the method further comprises: determining, based on theconfiguration information of the video service transmission system,whether the video service transmission system comprises a retransmissionserver, and when the video service transmission system comprises theretransmission server, obtaining an identifier of the retransmissionserver; and obtaining the retransmitted video stream further comprises:obtaining, based on the identifier of the to-be-monitored channel, theidentifier of the to-be-monitored user equipment, and the identifier ofthe retransmission server, a retransmitted packet sent by theretransmission server to the to-be-monitored user equipment, anddetermining the retransmitted packet as the retransmitted video stream.13. The method according to claim 12, wherein: the identifier of theto-be-monitored user equipment is an IP address of the to-be-monitoreduser equipment, and the identifier of the retransmission server is an IPaddress of the retransmission server; and when the retransmission serverand another device have a same IP address, obtaining, based on theidentifier of the to-be-monitored channel, the identifier of theto-be-monitored user equipment, and the identifier of the retransmissionserver, a retransmitted packet sent by the retransmission server to theto-be-monitored user equipment comprises: determining, based on theidentifier of the to-be-monitored channel, the IP address of theto-be-monitored user equipment, the IP address of the retransmissionserver, and an encapsulation format of a packet used to transmit a videostream, the retransmitted packet sent by the retransmission server tothe to-be-monitored user equipment.
 14. The method according to claim 9,wherein: the configuration information of the video service transmissionsystem comprises a buffer capacity of the to-be-monitored userequipment; and before obtaining the multicast video stream and theretransmitted video stream of the to-be-monitored channel, the methodfurther comprises: disposing of a buffer based on the buffer capacity ofthe to-be-monitored user equipment, wherein the buffer is configured tobuffer the multicast video stream and the retransmitted video stream.